Cage holder for spinal fusion cage

ABSTRACT

The present invention provides a cage holder for a spinal fusion cage which is mounted on the spinal fusion cage, thereby allowing the spinal fusion cage to be stably inserted between vertebral bodies. The cage holder may be engaged with the spinal fusion cage to insert the spinal fusion cage between the vertebral bodies at the lowest height, and may be reliably separated from the spinal fusion cage after the surgery. In addition, when mounting the cage holder on a height adjustable spinal fusion cage, the cage holder may visually indicate an amount of change in the height of the spinal fusion cage.

TECHNICAL FIELD

The present invention relates to a cage holder for a spinal fusion cage,and more specifically, to a cage holder for a spinal fusion cage whichis mounted on the spinal fusion cage, thereby allowing the spinal fusioncage to be stably inserted between vertebral bodies.

BACKGROUND ART

A vertebral body includes 32 to 35 vertebrae forming a body, andintervertebral disks, i.e., spinal disks arranged between the vertebrae,and is a portion forming a backbone of a human body that connects anupper skull and a lower pelvis to form the pillar of the truncus.

The spine includes 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbarvertebrae, 5 sacral vertebrae, and 3 to 5 coccyges from the top. In thecase of an adult, 5 sacral vertebrae are fused together to form onesacral vertebra, and 3 to 5 coccyges are fused together to form onetailbone.

As one of the treatment methods for treating serious spinal diseases fora long time, there is spinal fusion. Such spinal fusion is a surgicalmethod which includes removing an intervertebral disc, and inserting acage that replaces the intervertebral disc to fuse adjacent vertebralbodies to each other.

When performing the spinal fusion in the lumbar vertebrae, it may bedivided into posterior lumbar interbody fusion (PLIF), transforaminallumbar interbody fusion (TLIF), direct lateral lumbar interbody fusion(DLIF), oblique lumbar interbody fusion (OLIF), and anterior lumbarinterbody fusion (ALIF) depending on an insertion direction of the cage.

The PLIF is a method which includes incising a back along a centerlineof the spine, opening so as to expose all of the vertebral bodies,removing a portion of the posterior side of the vertebra, then removingthe disc, and inserting a PLIF cage between the vertebrae.

The PLIF has been performed from the oldest among the spinal fusions,and is an absolutely necessary method when fusing two or three joints.However, due to a surgical process, the PLIF has various disadvantagessuch as high possibility of adhesion to nerves, ligaments and muscles,extended period of time for a healing time due to a large incision area,and great aftereffects for some people.

The PLIF cage is the smallest of the cages used in all spinal fusions,wherein a pair of small cages are displaced on left and right sides ofthe spine.

The TLIF is a surgical method which includes incising the back in asmall area along both sides of a spinal muscle, exposing the vertebralbodies to a minimum, and then inserting the TLIF cage by replacing thedisc while removing a spinal joint site in a direction coming out of aneuropore. This surgical technique is suitable for a case of one jointdue to advantages of less bleeding, and reduced operation time. However,if an operation over multiple sites is required, the PLIF surgery shouldbe performed. Most of the TLIF cage is formed in an arch shape, suchthat it is placed in the vertebral bodies and rotated so that a convexportion of the TLIF cage faces a stomach. The TLIF cage is larger thanthe PLIF cage, but a support area is smaller than a DLIF cage or ALIFcage which will be described below.

The ALIF has various advantages, such as fast recovery from theoperation and no need to worry about adhesions. However, the ALIF has adisadvantage that highly advanced skill is needed because the operationis performed by incising an anterior (stomach) to bypass intestines, andapproaching the spine. The ALIF cage has an advantage of having thelargest support area among all spinal fusion cages.

The LLIF was developed to overcome the disadvantages of the ALIF, PLIF,and TLIF. Since the operation is performed through flank incision, theLLIF has advantages that an interval of stenosed sites between thevertebrae may be more greatly widened than the conventional surgeriesperformed by incision of the back, and there is almost no damage tosurrounding tissues. However, since a psoas muscle and peritoneum arearranged around a route to be operated, there is a problem of causingthigh muscle paralysis if there is a mistake during the operation. TheDLIF cage is smaller than the ALIF cage, but larger than the PLIF cageor TLIF cage.

Compared to the LLIF, the safer and more effective method is the OLIF(it can be called by ATP). The OLIF has advantages that the operationroute is formed in a direction inclined from the flank, and theoperation is possible between the fourth lumbar vertebra (L4) and the5th lumbar vertebra (L5), which are difficult to operate by the DLIF dueto the psoas muscle and peritoneum. In addition, the possibility ofdamaging the nerves, which may be a problem in the DLIF, issignificantly less.

Conventional spinal fusion cages are made of a single body with nochange in cross-sectional area or height using a metallic material suchas titanium or a polymeric material such as PEEK. Because of this, ithas a large number of products in consideration of the patient'sphysique, height, race, sex, etc. In other words, the manufacturer has aburden to combine the three variables of width, length and height toproduce at least tens to hundreds of products.

In addition, the interval between the vertebra of the patient does notincrease at regular intervals, but if produced in a single group,because it is necessary to select the appropriate height from thealready existing product range, there is a problem that cannot properlycope with each patient.

Various attempts have been made to solve the above-described problems,and a height adjustable spinal fusion cage has been developed.

U.S. Pat. No. 6,176,882 discloses such a height adjustable cage. Thecage of U.S. Pat. No. 6,176,882 includes a rectangular box-shaped wallwhose top and bottom are opened, engagement members which movevertically inside the wall, a pair of wedge members for pressing theengagement member, and an adjusting element which is screwed with thewedge members to adjust a spacing of the pair of wedge members.Therefore, U.S. Pat. No. 6,176,882 has a problem that the engagementmembers and the wedge members are only blocked by the box-shaped wall,and they are not connected to each other, such that the engagementmembers are shaken.

For comparison, U.S. Pat. No. 9,034,041 discloses, in an invention ofclaim 1 thereof, a cage generally including a body assembly, an uppersupport member 718 (hereinafter, not illustrated), and a lower supportmember 720, wherein the body assembly has a first portion 712 and asecond portion 714, and the first portion 712 and the second portion 714move on a longitudinal axis by a control member. The spacing between theupper support member 718 and the lower support member 720 is defined bya pair of first upper retaining members and a pair of second upperretaining members. Therefore, U.S. Pat. No. 9,034,041 has a problem thatthe cage does not include a component for directly guiding the mutualmovement of the upper support member 718 and the lower support member720, thus the body assembly, the upper support member 718 and the lowersupport member 720 are shaken with respect to each other.

US2017-02580605A discloses a holder 400 for a height adjustable cage asillustrated in FIGS. 26 to 29 thereof. US2017-02580605A uses a method inwhich, a plurality of arms 402 (hereinafter, not illustrated) areinserted into or protrude from a sleeve 410, then protrusions 404 formedon ends of the arms 402 are mounted in grooves 320 of a cage 300 to fixthe cage 300. However, such a method has a problem that, since the arm402 is extended by an elasticity thereof, there is a high possibilitythat the holder 400 may not be separated with being coupled to animplant 302 due to repeated use or obstruction of surrounding muscles atthe surgical site. In addition, in the existing cage holder, a change inthe height of the cage cannot be accurately grasped, and an operatordetermines it based on the experience thereof.

PRIOR ART DOCUMENT Patent Document

(Patent Document 1) U.S. Pat. No. 6,176,882

(Patent Document 2) U.S. Pat. No. 9,034,041

(Patent Document 3) U.S. Patent Application Publication No.US2017-02580605A

SUMMARY OF INVENTION Problems to be Solved by Invention

An object of the present invention is to provide a cage holder for aspinal fusion cage which is mounted on the spinal fusion cage, therebyallowing the spinal fusion cage to be stably inserted between vertebralbodies, and to be reliably separated from the spinal fusion cage afterthe surgery.

In addition, another object of the present invention is to provide acage holder for a spinal fusion cage capable of visually indicating anamount of change in a height of the spinal fusion cage when mounting onthe spinal fusion cage.

Means for Solving Problems

To achieve the above objects, according to an aspect of the presentinvention, there is a cage holder including: a main body; a holding bodywhich is inserted into the main body to relatively move with respect tothe main body, and has a pair of end effectors that protrude outwardlyfrom one end of the main body; a fastener integrally formed with theholding body; and a knob mounted on the other end of the main body andmovably coupled to the fastener in a longitudinal direction of the mainbody, wherein the end effectors are formed at ends of legs that branchout from one end of the holding body, and a guide unit is formed at theone end of the main body and the legs to forcibly guide the legs, whenthe holding body moves toward the one end of the main body in thelongitudinal direction thereof to increase a protruded length of the endeffectors, an interval between the pair of end effectors is enlarged,and when the holding body moves back from the one end of the main bodyin the longitudinal direction thereof to decrease the protruded lengthof the end effectors, the interval between the pair of end effectors isnarrowed.

The guide unit may include: guide sections longitudinally formed in thelegs; and fixing guides disposed in the main body and inserted into theguide sections.

The guide sections may be formed as guide slots which are elongated in alongitudinal direction of the legs with vertically penetrating the same,and the fixing guides may be guide pins which are fixed to the main bodyby passing through the guide slots.

The legs have bending notches formed on outer surfaces thereof, thus toincrease an amount of bending.

A driver may be inserted through insides of the fastener and the holdingbody, and the fastener may include an indication device configured toindicate an amount of rotation of the driver by converting it into anamount of change in a length thereof.

The indication device may include: a marking portion connected to thefastener; a movement conversion rod which is inserted into the markingportion and has a driver seat formed therein, on which the driver isseated; and a moving indicator which is screwed with the movementconversion rod and is exposed to an outside through a marking portionslot formed in the marking portion, so as to move along the markingportion slot according to a rotation of the movement conversion rod whenrotating the driver.

Two or more marking portion slots may be formed in the marking portion.

A pitch of a threaded portion formed on the movement conversion rod maybe greater than a pitch of a threaded portion formed on an adjustingmember configured to adjust a height of a cage.

The threaded portion formed on the movement conversion rod may be athread having a plurality of threaded-lines.

The moving indicator may include a movement indication protrusioninserted into the marking portion slot to be moved within a limitedrange by a length of the marking portion slot.

In addition, according to another aspect of the present invention, thereis a cage holder including: a main body; a holding body which isinserted into the main body to relatively move with respect to the mainbody, and has a pair of end effectors that protrude outwardly from oneend of the main body; a fastener integrally formed with the holdingbody; and a knob mounted on the other end of the main body and movablycoupled to the fastener in a longitudinal direction of the main body,wherein a driver is inserted through insides of the fastener and theholding body, and the fastener may include an indication deviceconfigured to indicate an amount of rotation of the driver by convertingit into an amount of change in a length thereof.

The indication device may include: a marking portion connected to thefastener; a movement conversion rod which is inserted into the markingportion and has a driver seat formed therein, on which the driver isseated; and a moving indicator which is screwed with the movementconversion rod and is exposed to an outside through a marking portionslot formed in the marking portion, so as to move along the markingportion slot according to a rotation of the movement conversion rod whenrotating the driver.

Two or more marking portion slots may be formed in the marking portion.

A pitch of a threaded portion formed on the movement conversion rod maybe greater than a pitch of a threaded portion formed on an adjustingmember configured to adjust a height of a cage.

The threaded portion formed on the movement conversion rod may be athread having a plurality of threaded-lines.

The moving indicator may include a movement indication protrusioninserted into the marking portion slot to be moved within a limitedrange by a length of the marking portion slot.

The end effectors may be formed at ends of legs that branch out from oneend of the holding body, and a guide unit is formed at the one end ofthe main body and the legs to forcibly guide the legs, when the holdingbody moves toward the one end of the main body in the longitudinaldirection thereof to increase a protruded length of the end effectors,an interval between the pair of end effectors may be enlarged, and whenthe holding body moves back from the one end of the main body in thelongitudinal direction thereof to decrease the protruded length of theend effectors, the interval between the pair of end effectors may benarrowed.

The guide unit may include: guide sections longitudinally formed in thelegs; and fixing guides disposed in the main body and inserted into theguide sections.

The guide sections may be formed as guide slots which are elongated in alongitudinal direction of the legs with vertically penetrating the same,and the fixing guides may be guide pins which are fixed to the main bodyby passing through the guide slots.

The legs may have bending notches formed on outer surfaces thereof, thusto increase an amount of bending.

Further, according to another aspect of the present invention, there isa cage holder including: a main body; a holding body which is insertedinto the main body to relatively move with respect to the main body, andhas a pair of end effectors that protrude outwardly from one end of themain body; a fastener integrally formed with the holding body; and aknob mounted on the other end of the main body and movably coupled tothe fastener in a longitudinal direction of the main body, wherein theend effectors are formed at ends of legs that branch out from one end ofthe holding body, and a guide unit is formed at the one end of the mainbody and the legs to forcibly guide the legs, when the holding bodymoves toward the one end of the main body in the longitudinal directionthereof to increase a protruded length of the end effectors, an intervalbetween the pair of end effectors is enlarged, and when the holding bodymoves back from the one end of the main body in the longitudinaldirection thereof to decrease the protruded length of the end effectors,the interval between the pair of end effectors is narrowed, an a driveris inserted through insides of the fastener and the holding body, andthe fastener may include an indication device configured to indicate anamount of rotation of the driver by converting it into an amount ofchange in a length thereof.

Advantageous Effects

According to the present invention, it is possible to operate so thatcages having different heights within a certain range can be replaced byone height adjustable cage. Therefore, the number of product groups thatshould be produced is reduced and the amount in stock is also decreasedon the manufacturer. In addition, unlike the cage having a predeterminedheight at a constant interval in the prior art, the height of the spinalfusion cage is linearly adjusted according to a spacing betweenvertebral bodies of a patient, such that the surgery may be performed atthe optimal height according to spinal conditions of the patient.

In addition, an amount of increase in the height of the cage can bevisually checked, thereby offering a sense of stability to a doctor, aswell as allowing the doctor to more precisely perform the surgery.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a spinal fusion cage according toEmbodiment 1 of the present invention with being the lowest height;

FIG. 2 is a perspective view of the spinal fusion cage shown in FIG. 1with being the highest height;

FIG. 3 is an exploded perspective view of the spinal fusion cage shownin FIG. 1;

FIG. 4 is an exploded perspective view of the spinal fusion cage shownin FIG. 1 as seen from the top, except for an adjusting member.

FIG. 5 is an exploded perspective view of the spinal fusion cage shownin FIG. 1 as seen from the bottom, except for the adjusting member.

FIG. 6 is a perspective view of a spinal fusion cage according toEmbodiment 2 of the present invention with being the lowest height;

FIG. 7 is a perspective view of the spinal fusion cage shown in FIG. 6with being the highest height;

FIG. 8 is an exploded perspective view of the spinal fusion cage shownin FIG. 6;

FIG. 9 is an exploded perspective view of the spinal fusion cage shownin FIG. 6 as seen from the top, except for an adjusting member.

FIG. 10 is an exploded perspective view of the spinal fusion cage shownin FIG. 6 as seen from the bottom, except for the adjusting member.

FIG. 11 is a perspective view of a cage holder according to anembodiment of the present invention;

FIG. 12 is a perspective view in cross-section of the cage holder shownin FIG. 11;

FIG. 13 is a partially enlarged cross-section of the cage holder shownin FIG. 11;

FIG. 14 is an exploded perspective view of the cage holder shown in FIG.11;

FIG. 15 is a perspective view in cross-section of the cage holder shownin FIG. 11 in an exploded state;

FIG. 16 is a perspective view of a main body;

FIG. 17 is a perspective view of a holding body;

FIG. 18 is a partially enlarged plan view of the holding body shown inFIG. 16;

FIG. 19 is a plan view of the cage holder on an end effector side shownin FIG. 11 in the exploded state;

FIG. 20 is a perspective view of a knob;

FIG. 21 is a perspective view of a fastener;

FIG. 22 is a perspective view of the movement conversion rod;

FIG. 23 is a perspective view of a moving indicator;

FIG. 24 is a perspective view of a retainer;

FIG. 25 is a perspective view of the spinal fusion cage with being closeto the cage holder of Embodiment 1; and

FIG. 26 is a perspective view of the spinal fusion cage of Embodiment 1in the maximum height due to the cage holder coupled thereto.

MODE FOR CARRYING OUT INVENTION

Hereinafter, the present invention will be described in detail withreference to the accompanying drawings. In denoting reference numeralsto constitutional elements of respective drawings, it should be notedthat the same elements will be denoted by the same reference numeralsalthough they are illustrated in different drawings. In the embodimentsof the present invention, the publicly known functions andconfigurations that are judged to be able to make the purport of thepresent invention unnecessarily obscure will not be described.

FIGS. 1 to 5 illustrate a spinal fusion cage 100 according to Embodiment1 of the present invention, and FIGS. 6 to 10 illustrate a spinal fusioncage 200 according to Embodiment 2 of the present invention.Hereinafter, the same components of Embodiment 1 and Embodiment 2 willbe described together, and then differences between Embodiment 1 andEmbodiment 2 will be described, respectively.

The spinal fusion cages 100, 200 according to Embodiments 1, 2 will bedescribed with reference to FIGS. 1 to 5, and 6 to 10. The spinal fusioncages 100, 200 may include: First endplates 102, 202 and secondendplates 120, 220 which are disposed vertically to face each other;distal moving blocks 140, 240 and proximal moving blocks 170, 270 whichare disposed between the first endplates 102, 202 and the secondendplates 120, 220 to move according to a distance between the firstendplates 102, 202 and the second endplates 120, 220; and adjustingmembers 180, 280 which are connected to the distal moving blocks 140,240 by passing through the proximal moving blocks 170, 270.

The first endplates 102, 202 and the second endplates 120, 220 havefirst plate portions 104, 204 and second plate portions 122, 222configured to abut vertebral bodies. The first plate portions 104, 204and the second plate portions 122, 222 may have teeth formed thereon toprevent the vertebral bodies from separating from each other. Inaddition, first windows 118, 218, and second windows 138, 238 forinserting bone grafts are formed at central portions of the first plateportions 104, 204 and the second plate portions 122, 222, respectively.

First plate rails 111, 211, second plate rails 112, 212, third platerails 113, 213, and fourth plate rails 114, 214 are formed on both sidesof the first plate portions 104, 204 in a longitudinal direction. Thefirst plate rails 111, 211 and the second plate rails 112, 212 arelocated to face each other in a distal direction, and first platerecesses 110, 210 are formed between these rails. The third plate rails113, 213 and the fourth plate rails 114, 214 are located to face eachother in a proximal direction, and second plate recesses 116, 216 areformed between these rails. All the first plate rails 111, 211, thesecond plate rails 112, 212, the third plate rails 113, 213, and thefourth plate rails 114, 214 are formed in the surfaces of the firstplate portions 104, 204 slantly extending upward in a thicknessdirection from ends toward the center of the first plate portions 104,204 with being close to each other.

Similarly, fifth plate rails 131, 231, sixth plate rails 132, 232,seventh plate rails 133, 233, and eighth plate rails 134, 234 are formedon both sides of the second plate portions 122, 222 in the longitudinaldirection. The fifth plate rails 131, 231 and the sixth plate rails 132,232 are disposed to face each other in the distal direction, and thirdplate recesses 130, 230 are formed between these rails. In addition, theseventh plate rails 133, 233 and the eighth plate rails 134, 234 arelocated to face each other in the proximal direction, and fourth platerecesses 136, 236 are formed between these rails. All the fifth platerails 131, 231, the sixth plate rails 132, 232, the seventh plate rails133, 233, and the eighth plate rails 134, 234 are formed in the surfaceof the second plate portions 122, 222 slantly extending upward in thethickness direction from ends toward the center of the second plateportions 122, 222 with being close to each other.

The distal moving blocks 140, 240 have insertion portions 142, 242formed therein by protruding in a streamlined shape so as to be easilyinserted between the vertebral bodies in the proximal direction. Inaddition, the distal moving blocks 140, 240 have connecting rods 144,244 formed therein by elongating in the distal direction, and connectingthreaded holes 150, 250 having a thread are formed inside the connectingrods 144, 244. Further, the distal moving blocks 140, 240 have firstblock projections 146, 246 formed thereon so as to correspond to thefirst plate recesses 110, 210 of the first endplates 102, 202, andsecond block projections 148, 248 formed thereon so as to correspond tothe third plate recesses 130, 230 of the second endplates 120, 220.First block rails 151, 251 and second block rails 152, 252 correspondingto the first plate rails 111, 211 and the second plate rails 112, 212are formed around the first block projections 146, 246. Fifth blockrails 151, 251 and sixth block rails 162, 262 corresponding to the fifthplate rails 131, 231 and the sixth plate rails 132, 232 are formedaround the second block projections 148, 248.

The proximal moving blocks 170, 270 have through holes 178, 278 formedtherein to rotatably support the adjusting members 180, 280. Inaddition, the proximal moving blocks 170, 270 have third blockprojections 172, 272 formed thereon so as to correspond to the secondplate recesses 116, 216 of the first endplates 102, 202, and fourthblock projections 174, 274 formed thereon so as to correspond to thefourth plate recesses 136, 236 of the second endplates 120, 220. Thirdblock rails 153, 253 and fourth block rails 154, 254 corresponding tothe third plate rails 113, 213 and the fourth plate rails 114, 214 areformed around the third block projections 172, 272. Seventh block rails163, 263 and eighth block rails 164, 264 corresponding to the seventhplate rails 133, 233 and the eighth plate rails 134, 234 are formedaround the fourth block projections 174, 274. In addition, fixing pinholes 176, 276, into which fixing pins 192, 194; 292, 294 are inserted,are formed on sides of the proximal moving blocks 170, 270. Further,engagement portions 166, 266 are formed on the sides of the proximalmoving blocks 170, 270 to grip the spinal fusion cages 100, 200 by atool.

The distal moving blocks 140, 240 and the proximal moving blocks 170,270 have a substantially wedge shape, and are configured to move thefirst endplates 102, 202 and the second endplates 120, 220 by pressingup or down.

The adjusting members 180, 280 may have a shape of a substantially bolt.That is, the adjusting members 180, 280 have heads 182, 282 andadjusting threaded portions 188, 288. The heads 182, 282 are seated inopenings formed in the through holes 178, 278 in the proximal directionthereof, and the adjusting threaded portions 188, 288 pass through thethrough holes 178, 278, and are screwed to the threaded holes 150, 250of the connecting rods 144, 244. Tool seats 190, 290 are formed in heheads 182, 282, which may be connected with a tool (not shown). Inaddition, support portions 186, 286 are located between the heads 182,282 and the through holes 178, 278, and are rotatably supported by innerwall surfaces of the through holes 178, 278 while abutting the same. Inaddition, pin seats 184, 284 are formed around the support portions 186,286 such that end portions of the fixing pins 192, 194; 292, 294inserted through the pin holes 176, 276 of the proximal moving blocks170, 270 are seated. As a result, the adjusting members 180, 280 can berotated in position.

A pair of columns 108, 208 is formed on both sides of the first plateportions 104, 204 in the thickness direction, that is, in a directiontoward the second endplates 120, 220. Further, receiving recesses 106,206, in which extension walls 124, 224 can be received as describedbelow, are formed around the columns 108, 208. In addition, a pair ofextension walls 124, 224 are formed on both sides of the secondendplates 120, 220 in the thickness direction, that is, in the directiontoward the first endplates 102, 202, and recesses 126, 226, into whichthe columns 108, 208 can be inserted and guided, are formed inside ofthe extension walls 124, 224. As a result, when the columns 108, 208 areinserted into the recesses 126, 226 and move vertically, movements ofthe first endplates 102, 202 and the second endplates 120, 220 indirections in which they are close to or spaced apart from each otherare blocked.

In addition, the extension walls 124, 224 includes first walls 1241,2241 and second walls 1242, 2242 which are located at a front end and arear end of the columns 108, 208 in the longitudinal direction of thesecond endplates 120, 220, and third walls 1243, 2243 which connect thefirst walls 1241, 2241 and the second walls 1242, 2242 to form therecesses 126, 226 into which the columns 108, 208 are inserted. That is,the extension walls 124, 224 are formed to surround the columns 108, 208while having a substantially U shape when viewing from the top.

The first walls 1241, 2241 and the second walls 1242, 2242 are formed soas to have thicknesses smaller than a value of excluding widthwiselengths of the second windows 138, 238 from widthwise lengths of thesecond plate portions 122, 222. The reason is that the first walls 1241,2241 and the second walls 1242, 2242 are inserted into the receivingrecesses 106, 206 of the first endplates 102, 202. In addition, thecolumns 108, 208 may be formed so as to have widthwise thicknessesgreater than ¼ times and smaller than ½ times of a value of excludingthe widthwise lengths of the first windows 118, 218 from the widthwiselengths of the first plate portions 104, 204. The reason is that thecolumns 108, 208 are thickened by depths of the recesses 126, 226 intowhich the columns 108, 208 are inserted.

In addition, guide grooves 128, 228 may be formed in the first walls1241, 2241 and the second walls 1242, 2242 to guide the columns 108, 208to be inserted into the recesses 126, 226. The reason is that thethicknesses of the columns 108, 208 are larger than the thicknesses ofthe first walls 1241, 2241 and the second walls 1242, 2242.

In addition, the spinal fusion cage 100 of Embodiment 1 and the spinalfusion cage 200 of Embodiment 2 have different positions relative to thefirst endplates 102, 202 and the second endplates 120, 220 at the lowestheight.

The spinal fusion cage 100 of Embodiment 1 is formed so that a firstbottom surface 105 of the first endplate 102 abuts a second bottomsurface 123 of the second endplate 120 when it is at its lowest state.

On the other hand, the spinal fusion cage 200 of Embodiment 2 is formedso that a first bottom surface 205 of the first endplate 202 abutsstoppers 229 formed on the first wall 2241 and the second wall 2242 ofthe second endplate 220 when it is at its lowest state. The stopper 229protrudes from the first wall 2241 and the second wall 2242 so as toabut around the receiving recess 206 of the first bottom surface 205 ofthe first endplate 202.

As a result, when the spinal fusion cage 200 of Embodiment 2 is at itslowest state, the first bottom surface 205 of the first endplate 202 andthe second bottom surface 223 of the second endplate 220 are spacedapart from each other.

Like the spinal fusion cage 200 of Embodiment 2, when the height thereofin the lowest state is higher than that of the spinal fusion cage 100 ofEmbodiment 1, there is a limitation in the length of the spinal fusioncage 200 to be inserted into the vertebral bodies, and the proximalmoving block 270 and a longitudinal length of the spinal fusion cage 200of the distal moving block 240 is not changed. Therefore, in order tomaintain a driving force of the adjusting member 280 in the same levelas that of Embodiment 1, the first to eighth block rails and inclinationdegrees of the first to eighth plate rails should be the same as thoseof the spinal fusion cage 100 of Embodiment 1. Therefore, the firstbottom surface 205 of the first endplate 202 and the second bottomsurface 223 of the second endplate 220 need to be spaced apart from eachother, and the spinal fusion cage of Embodiment 2 further includes thestopper 229.

The spinal fusion cages 100, 200 are configured as described above, andby inserting a tool such as a driver into tool grooves 190, 290 androtating it in one direction, it is possible to perform movements inwhich the proximal moving blocks 170, 270 and the distal moving block140 are close to each other, and consequently, the first endplates 102,202 and the second endplates 120, 220 are spaced apart from each other.Similarly, by inserting the tool and rotating in the other direction, itis possible to perform the movement in which the proximal moving blocks170, 270 and the distal moving blocks 140, 240 are spaced apart fromeach other, and consequently, a distance between the first endplates102, 202 and the second endplates 120, 220 is decreased.

According to such spinal fusion cages 100, 200, cages having differentheights within a certain range may be replaced by one cage, such that itis possible to reduce burdens on the stock and production, decrease therepetitive work during the surgery, thus to reduce the labor of thedoctor. In addition, since the operation time is also reduced, theamount of bleeding is reduced, a recovery time of the patient may besignificantly shortened, such that the spinal fusion cage of the presentinvention may be expected to be widely used in the related field due tothe above-described advantages.

Next, a cage holder 300 according to the embodiment of the presentinvention will be described with reference to FIGS. 11 to 24.

The cage holder 300 generally includes: a main body 302; a holding body304 which is inserted into the main body 302 to relatively move withrespect to the main body 302, and has a pair of end effectors 344 and346 that protrude outwardly from one end of the main body 302; afastener 308 integrally formed with the holding body 304; and a knob 306mounted on the other end of the main body 302 and movably coupled to thefastener 308 in the longitudinal direction of the main body 302.

The end effectors 344 and 346 are formed at ends of legs 330 and 332that branch out from one end of the holding body 304, and a guide unitmay be formed at the one end of the main body 302 and the legs 330 and332 to forcibly guide the legs 330 and 332.

In addition, a driver 310 may be inserted through insides of thefastener 308 and the holding body 304, and the fastener 308 may furtherinclude an indication device capable of indicating an amount of rotationof the driver by converting it into an amount of change in a lengththereof.

Each of or both of the guide unit and the indication device may beincluded in the cage holder 300.

As illustrated in FIG. 16, the main body 302 includes a main body tube312 having a main body hole 326 formed therein, and one or more cleaningholes 314 disposed in length direction thereof to facilitate cleaning.The main body tube 312 has an opening 320 formed in one end thereof tocommunicate with the main body hole 326, and the end effectors 344 and346 that protrude outwardly through the opening 320.

When viewing the main body 302 from the top, an end portion of theopening 320 is formed in a substantially straight line, but may beconcavely or convexly formed in accordance with the shape of theproximal portion of the spinal fusion cage.

An extension portion 316 is disposed on one side of the main body tube312. The expansion part 316 is enlarged in a width direction (consistentwith the width direction of the cage) from the main body tube 312, sothat the end effectors 344 and 346 formed at the ends of the legs 330and 332 are extended in the width direction.

The guide unit may be disposed on the extension portion 316 side, andmay include guide sections longitudinally formed in the legs 330 and332, and fixing guides disposed in the main body 302 and inserted intothe guide sections.

In the embodiment of the present invention, the guide sections areformed as guide slots 340 and 342 which are elongated in a longitudinaldirection of the legs 330 and 332 with vertically penetrating the same,and the fixing guides are guide pins 406 and 408 which are fixed to themain body 302 by passing through the guide slots 340 and 342. The mainbody tube 312 has a guide pin hole 318 formed in one end thereof, intowhich the guide pins 406 and 408 are inserted to be installed.

A fitting groove 324 is formed in the other end of the main body tube312, to which the knob 306 is fitted. In addition, as illustrated inFIG. 16, a locking jaw 322 is formed at the other end of the main bodytube 312 far away from the fitting groove 324, which serves to preventthe knob 306 from being removed.

As illustrated in FIGS. 17 and 18, the holding body 304 has a holdingbody tube 328 inserted into the main body 302, and one end thereof formstwo legs 330 and 332 that branch out from a branch point 334. The legs330 and 332 have bending notches 336 and 338 formed on outer surfacesthereof, thereby serving to increase an amount of bending.

The end effectors 344 and 346 are disposed at the ends of the legs 330and 332 to grip the cage. In addition, the guide slots 340 and 342 areformed in the legs 330 and 332 as described above.

FIG. 19 illustrates a state in which the legs 330 and 332 are arrangedin the extension portion 316 of the main body 302. In this state, guidepins 406 and 408 are inserted into the guide slots 340 and 342 formed inthe legs 330 and 332. Therefore, when the holding body 304 moves towardthe one end of the main body 302 in the longitudinal direction thereofto increase a protruded length of the end effectors 344 and 346, aninterval between the pair of end effectors 344 and 346 is enlarged. Onthe other hand, when the holding body 304 moves back from the one end ofthe main body 302 in the longitudinal direction thereof to decrease theprotruded length of the end effectors 344 and 346, the interval betweenthe pair of end effectors 344 and 346 is narrowed. That is, it ispossible to forcibly enlarge or reduce the legs 330 and 332 by theabove-described guide pins 406 and 408 and the guide slots 340 and 342.

A coupling portion 350 is formed at the other end of the holding body304 to be fixed to the fastener 308. The coupling portion 350 may befixed to the holding body 304 by a method using well-known techniquessuch as screwing by threads, welding, fixing using pins, epoxy bondingand the like.

As illustrated in FIG. 20, the knob 306 serves to apply a rotationalforce to move the holding body 304 with respect to the main body 302. Tothis end, the knob 306 include: a knob body 352 having irregularitiesformed on an outer circumference thereof so as to facilitate gripping byhand; a fitting step 354 formed on an inner surface thereof to be fittedto the fitting groove 324 of the main body 302; and a knob thread 356formed on the inner surface thereof to be screwed with a fastener thread362 formed on the fastener 308 to be described below. The knob 306 has aknob hole 358 formed therein to have a tube shape as a whole.

As illustrated in FIG. 21, the fastener 308 includes a fastener body 360having the fastener thread 362 formed at one end thereof, and a markingportion 364 formed at the other end thereof. The marking portion 364 isa tube body communicating with the fastener hole 368 of the fastener308, and has a plurality of marking portion slots 366 formed therein inthe longitudinal direction. The marking portion 364 may have a fastenerguide section 370 formed on an inner wall surface of the fastener hole368, into which a moving indicator 380 is inserted.

In addition, the fastener 308 may have a handle coupling portion 372formed on the outer circumference thereof, to which a handle 392 isinserted to be fixed. The handle 392 may have a connecting chuck 394(FIG. 14) formed at one end thereof, to which an additional handle iscoupled.

A scale capable of indicating a length is displayed on an outercircumference of the marking portion 364, and the height of the currentcage can be indicated by a marker displayed on the moving indicator 380.

Then, a movement conversion rod 376 is inserted into the marking portion364 through the fastener hole 368 to be rotatably supported by arotational support ring 374. The movement conversion rod 376 has athread formed on an outer circumference thereof, and the thread isscrewed with a moving indicator threaded portion 386 formed on an innercircumference of the moving indicator 380. If a pitch of the threadformed on the movement conversion rod 376 is the same as the pitch ofthe thread formed on the adjusting member of the cage, a movement amountof the moving indicator 380 is small and it is difficult to visuallygrasp. Therefore, the thread of the movement conversion rod 376 isgreater than the pitch of the thread of the adjusting member or has aplurality of threaded-lines so as to expand a lead of the adjustingmember.

In addition, the moving indicator 380 has a movement indicationprotrusion 384 formed around a moving indicator body 382 so as toprotrude from the marking portion slot 366 to be guided.

Finally, the moving indicator 380 is inserted into the marking portion364 of the fastener 308, and a retainer 388 is fastened to prevent themoving indicator 380 from being removed. The retainer 388 is fixed tothe end of the marking portion 364 using known techniques such asscrewing, welding, epoxy bonding and the like. The retainer 388 may havea retainer tool groove 390 formed therein to be engaged with the tool orthe like.

The driver 310 is inserted through the fastener 308 and a holding bodyhole 348 formed in the holding body 304. The driver 310 may have a drivetip 398 formed at one end of a shaft 396 thereof to be engaged with theadjusting member of the cage. In addition, the driver 310 may have adriver coupling portion 400 formed at the other end thereofcorresponding to a driver seat 378 formed on the inner surface of theopening formed in the movement conversion rod hole 410 of the movementconversion rod 376. In addition, the driver 310 may have a driver chuck404 formed at the other end thereof to be engaged with the handle, whichis continued to the driver coupling portion 400 with the connecting rod402 interposed therebetween.

Next, a driving principle for moving the holding body 304 with respectto the main body 302 will be described with reference to FIGS. 13 and20.

The coupling ring 412 is inserted into and fixed to the fitting groove324 of the main body 302 and the fitting step 354 of the knob 306. Thus,the main body 302 and the knob 306 are fixed to each other, and the knob306 is rotatable with respect to the main body 302. The coupling portion350 of the holding body tube 328 is inserted into and fixed to thefastener 308. Accordingly, the fastener 308 and the holding body tube328 become one body. Then, the fastener thread 362 of the fastener 308and the knob thread 356 of the knob 306 are screwed with each other.

Accordingly, when rotating the knob 306, the knob thread 356 rotateswith respect to the fastener thread 362, thereby allowing the main body302 to be close to or be spaced apart from the fastener 308. As aresult, the holding body 304 integrally formed with the fastener 308moves forward and backward, and the legs 330 and 332 formed at one endof the holding body 304 also move forward and backward. The movement ofthe end effectors 344 and 346 due to the forward and backward movementof the legs 330 and 332 is as described above.

Next, the indication device will be described with reference to FIGS. 14and 15. The indication device includes: The marking portion 364connected to the fastener 308; the movement conversion rod 376 which isinserted into the marking portion 364 and has the driver seat 378 formedtherein, on which the driver 310 is seated; and the moving indicator 380which is screwed with the movement conversion rod 376 and is exposed toan outside through the marking portion slot 366 formed in the markingportion 364, so as to move along the marking portion slot 366 accordingto a rotation of the movement conversion rod 376 when rotating thedriver 310.

When the driver 310 is inserted and rotates while the driver couplingportion 400 and the driver seat 378 are engaged to each other, therotation of the driver 310 is transmitted to the movement conversion rod376. Then, the moving indicator 380 screwed with the movement conversionrod 376 is moved by the rotation of the movement conversion rod 376.When the movement indication protrusion 384 of the moving indicator 380moves at the outside along the marking portion slot 366, the height ofthe current cage may be determined by reading a position where themarking formed on the marking portion 364 matches the marking of themovement indication protrusion 384.

Next, FIG. 25 illustrates a state in which the spinal fusion cage 100and the cage holder 300 engaged with each other. The cage holder 300 isclose to the cage holder 300 in the lowest height sight, therebyallowing the end effectors 344 and 346 to be located around theengagement portions 166 formed on the sides of the spinal fusion cage100.

When rotating the knob 306 to move backward the holding body 304, theend effectors 344 and 346 are inserted into the engagement portions 166to fix the spinal fusion cage 100. At this time, since the shape of theopening 320 corresponds to the shape of the proximal moving block 170,they can be in close contact with each other, and thus the shaking ofthe spinal fusion cage 100 may be prevented.

Next, the driver 310 is inserted into the cage holder 300 and the drivetip 398 of the driver 310 is engaged to the tool groove 190 of theadjusting member 180. Thereafter, when rotating the driver 310, theadjusting member 180 is rotated, and thereby allowing the proximalmoving block 170 and the distal moving block 140 to be close to eachother, as well as, as illustrated in FIG. 25, the first endplate 102 andthe second endplate 120 are spaced apart from each other.

While the present invention has been described with reference to thepreferred embodiments, it will be understood by those skilled in therelated art that various modifications and variations may be madetherein without departing from the scope of the present invention asdefined by the appended claims.

INDUSTRIAL APPLICABILITY

According to the cage holder of the present invention, it is possible toinsert the spinal fusion cage between adjacent vertebral bodies, and maybe stably separated from the cage, thereby preventing accidents that mayoccur during the surgery.

In particular, since the height of the cage between the implants may bedirectly confirmed by eyes from the outside of the surgical area, thesurgery may be accurately performed, such that it is more suitable forless experienced doctors.

DESCRIPTION OF REFERENCE NUMERALS

100, 200: Spinal fusion cage

102, 202: First endplate

104, 204: First plate portion

105, 205: First bottom surface

106, 206: Receiving recess

108, 208: Column

110, 210: First plate recess

111, 211: First plate rail

112, 212: Second plate rail

113, 213: Third plate rail

114, 214: Fourth plate rail

116, 216: Second plate recess

118, 218: First window

120, 220: Second endplate

122, 222: Second plate portion

123, 223: Second bottom surface

124, 224: Extension wall

126, 226: Recess

128, 228: Guide groove

130, 230: Third plate recess

131, 231: Fifth plate rail

132, 232: Sixth plate rail

133, 233: Seventh plate rail

134, 234: Eighth plate rail

136, 236: Fourth plate recess

138, 38: Second window

140, 240: Distal moving block

142, 242: Insertion portion

144, 244: Connecting rod

146, 246: First block projection

148, 248: Second block projection

150, 250: Connecting threaded hole

151, 251: First block rail

152, 252: Second block rail

153, 253: Third block rail

154, 254: Fourth block rail

161, 261: Fifth block rail

162, 262: Sixth block rail

163, 263: Seventh block rail

164, 264: Eighth block rail

166, 266: Engagement portion

170, 270: Proximal moving block

172, 272: Third block projection

174, 274: Fourth block projection

176, 276: Pin hole

178, 278: Through hole

180, 280: Adjusting member

182, 282: Head

184, 284: Pin seat

186, 286: Support portion

188, 288: Adjusting threaded portion

190, 290: Tool seat

192, 194, 292, 294: Fixing pin

229: Stopper

1241, 2241: First wall

1242, 2242: Second wall

1243, 2243: Third wall

300: Cage holder

302: Main body

304: Holding body

306: Knob

308: Fastener

310: Driver

312: Main body tube

314: Cleaning hole

316: Guide unit

318: Guide pin hole

320: Opening

322: Locking jaw

324: Fitting groove

326: Main body hole

328: Holding body tube

330, 332: Leg

334: Branch point

336, 338: Bending notch

340, 342: Guide slot

344, 346: End effector

348: Holding body hole

350: Coupling portion

352: Knob body

354: Fitting step

356: Knob thread

358: Knob hole

360: Fastener body

362: Fastener thread

364: Marking portion

366: Marking portion slot

368: Fastener hole

370: Fastener guide section

372: Handle coupling portion

374: Rotational support ring

376: Movement conversion rod

378: Driver seat

380: Moving indicator

382: Moving indicator body

384: Movement indication protrusion

386: Moving indicator threaded portion

388: Retainer

390: Retainer tool groove

392: Handle

394: Connecting chuck

396: Shaft

398: Drive tip

400: Driver coupling portion

402: Connecting rod

404: Driver chuck

406, 408: Guide pin

410: Movement conversion rod hole

412: Coupling ring

What is claimed is:
 1. A cage holder comprising: a main body; a holdingbody which is inserted into the main body to relatively move withrespect to the main body, and has a pair of end effectors that protrudeoutwardly from one end of the main body; a fastener integral with theholding body; and a knob mounted on the other end of the main body andmovably coupled to the fastener in a longitudinal direction of the mainbody, wherein a driver is inserted through insides of the fastener andthe holding body, and the fastener comprises an indication deviceconfigured to indicate an amount of rotation of the driver by convertingit into an amount of change in a length thereof; wherein the indicationdevice comprises: a marking portion connected to the fastener; amovement conversion rod which is inserted into the marking portion andhas a driver seat formed therein, on which the driver is seated; and amoving indicator which is screwed with the movement conversion rod andis exposed to an outside through a marking portion slot formed in themarking portion, so as to move along the marking portion slot accordingto a rotation of the movement conversion rod when rotating the driver.2. The cage holder according to claim 1, wherein two or more markingportion slots are formed in the marking portion.
 3. The cage holderaccording to claim 1, wherein a pitch of a threaded portion formed onthe movement conversion rod is greater than a pitch of a threadedportion formed on an adjusting member configured to adjust a height of acage.
 4. The cage holder according to claim 3, wherein the threadedportion formed on the movement conversion rod is a thread having aplurality of threaded-lines.
 5. The cage holder according to claim 1,wherein the moving indicator comprises a movement indication protrusioninserted into the marking portion slot to be moved within a limitedrange by a length of the marking portion slot.
 6. The cage holderaccording to claim 1, wherein the end effectors are formed at ends oflegs that branch out from one end of the holding body, and a guide unitis formed at the one end of the main body and the legs to forcibly guidethe legs, when the holding body moves toward the one end of the mainbody in the longitudinal direction thereof to increase a protrudedlength of the end effectors, an interval between the pair of endeffectors is enlarged, and when the holding body moves back from the oneend of the main body in the longitudinal direction thereof to decreasethe protruded length of the end effectors, the interval between the pairof end effectors is narrowed.
 7. The cage holder according to claim 6,wherein the guide unit comprises: guide sections longitudinally formedin the legs; and fixing guides disposed in the main body and insertedinto the guide sections.
 8. The cage holder according to claim 7,wherein the guide sections are formed as guide slots which are elongatedin a longitudinal direction of the legs, and the fixing guides are guidepins which are fixed to the main body by passing through the guide slotsin a direction perpendicular to the longitudinal direction of the guideslots formed in the legs.
 9. The cage holder according to claim 6,wherein the legs have bending notches formed on outer surfaces thereof,thus to increase an amount of bending.